This invention relates to nonintrusive scanning for materials (such as, for example, detection of explosives, nuclear materials, or contraband at airports, seaports, or other transportation terminals), and more particularly, to a method and apparatus for adaptive scanning using nuclear resonance fluorescence.
There are many requirements that scanning methods may desirably meet. First, it may be desirable that the measurements be reliable in detecting threats or contraband with a high probability of detection (DP) and a low probability of obtaining a false positive (FP). Further, it may be desirable that a scanning method operate as rapidly as possible while having a high rate of detection and a low rate of false positive events. Also, the searches may desirably be non-intrusive and non-destructive. Since the articles to be examined may be sizeable (such as shipping containers), the use of penetrating radiation is attractive; however, the radiation should preferably not leave the scanned article radioactive. The capability to image a target may also be of value. An adaptive method for optimally achieving these goals using Nuclear Resonance Fluorescence Imaging (NRFI) is presented here.